When the water retention capacity or barrier functions of the horny layer are weakened by some internal or external reasons, the skin suffers from troubles such as chapping and acceleration of aging. It is therefore highly important to maintain and reinforce the water retention capacity and barrier functions of the horny layer for our healthy daily life.
The present applicant has formerly proposed dermatologic preparations comprising an amide derivative represented by the following formula (3):
(wherein, Ra represents a linear or branched, saturated or unsaturated hydrocarbon group having 10 to 40 carbon atoms, Rb represents a linear or branched divalent hydrocarbon group having 3 to 39 carbon atoms, Rc represents a hydrogen atom, a linear or branched, saturated or unsaturated hydrocarbon group having 10 to 40 carbon atoms or an acyl group) as a dermatologic preparation capable of essentially improving (maintaining, reinforcing) the barrier functions of the horny layer (Japanese Patent Application Laid-Open (Kokai) No. 4-128256).
Although these amide derivatives exert the above-described excellent effects, they still involve some problems in miscibility or mixing stability because they do not always have sufficient solubility in bases and solution stability. Moreover, preparation of such amide derivatives requires multi-stage reaction, inevitably causing an increase in their production cost.
An object of the present invention is therefore to provide a compound capable of essentially improving the water retention capacity and barrier functions of the horny layer, having improved miscibility or mixing stability, and being available efficiently at a low cost; and a dermatologic preparation which contains the above-described compound and, by maintaining and reinforcing the water retention capacity and barrier functions of the horny layer, exerts effects of preventing or remedying skin troubles such as chapping, protecting the hair with its penetrated component, improving touch feel of the hair and preventing or remedying chapping of the scalp.